Fuelwood Savings Research Articles

Performance comparison of three prototype biomass stoves with traditional and Mirt stoves for baking Injera

Abstract Background Injera is food consumed daily by Ethiopians like bread and rice in other parts of the world. Biomass stoves are used to bake Injera in most rural households. The unsustainable use of fuelwood causes deforestation. Improved cook stoves such as Mirt (name in local language) were introduced to replace traditional stoves and save fuel wood. This study presents a performance comparison of three newly developed prototype biomass stoves with traditional and Mirt stoves. The prototype stoves were made with a clay pan (designated MUC: Mekelle University prototype with clay pan), with a glass pan (MUG) and with an aluminum pan (MUA). Controlled cooking tests were conducted for each type of stove to determine the thermal efficiency and specific fuel consumption. Results The thermal efficiencies of the traditional, Mirt, MUC, MUA and MUG stoves were found to be 14%, 17%, 21%, 29% and 32%, respectively. Similarly, the percentage fuel wood savings by Mirt, MUC, MUA and MUG compared to the traditional stove were 32%, 48%, 64% and 67%, respectively. The results indicate that the prototype stoves had significantly better performance compared to the traditional and Mirt stoves. Conclusion The prototype stoves have the potential to reduce fuel wood consumption by more than half of that currently consumed employing traditional stoves. In addition to the economic benefit of saving fuel wood, the improved stoves will have significant environmental implication. Based on the fuel saving figures, it is estimated that 0.4, 0.5 and 0.52 tons/year of fuel wood may be saved per household adopting MUC, MUA and MUG stoves, respectively.

Longitudinal analysis and expected evolution of household fuel and stove stacking patterns in rural Mexico

We conducted a longitudinal analysis of the multiple stacking options that emerge from a “Patsari” clean woodburning cookstove dissemination program in rural Mexico, directed to households with-and-without previous access to liquefied petroleum gas (LPG). The analysis is based on Kitchen Performance Tests applied to 134 households belonging to 10 villages of Central Mexico, where household fuelwood consumption before-and-after the installation of the Patsari cookstove was measured. The analysis showed that: a) from the initial two categories of users (Open Fire and LPG) the adoption of Patsari stoves led to the emergence of six categories of users or stacking options (Patsari-alone; Patsari-LPG; Patsari-LPG-Open fire; Patsari-Open Fire; LPG-Open Fire; Open Fire-alone); b) when LPG is used in combination with open fires, there are negligible fuelwood savings; c) the largest reduction in emissions with regards to open fires is observed for the Patsari-only users (47.5%); and d) the adoption of Patsari cookstoves led to 39% fuel savings for exclusive fuelwood users and 48% for mixed LPG-fuelwood users. We conducted a Markov Chain analysis to explore the likely future evolution of user groups assuming a continuation of the Patsari stove implementation program. We found that instead of a smooth transition from open fires to Patsari stoves, 62% of the users within five years would be expected to stack different cooking devices, while 34% of the users would only use the Patsari cookstove. It is also expected that 19.63% of households will continue using the open fires either alone or in combination with other stoves.

Do improved biomass cookstoves reduce fuelwood consumption and carbon emissions? Evidence from a field experiment in rural Ethiopia

Using a randomized experimental design, real-time electronic stove surface temperature measurements and controlled cooking tests, we estimate fuelwood and CO2 savings from an improved cookstove (ICS) program in rural Ethiopia. Cooking uses a majority of the fuelwood in the country and therefore is a critical determinant of greenhouse gas emissions. Estimating fuelwood savings is therefore a key aspect of crediting ICS climate change benefits. Our findings suggest that the Mirt injera stove saves a substantial amount of fuelwood. Using a relatively low estimate of percentage of nonrenewable biomass, on average one Mirt stove avoids the burning of approximately 634 kg of fuelwood per year and sequesters an additional 0.65 tons of CO2, which is about one-third of previous estimates. The U.S. Interagency Working Group (2013) 2015–2019 estimate for the global social cost of carbon of $44.00 per ton implies annual global benefits from reduced fuelwood burning of $28.60 per stove per year, which substantially exceeds the $12.00 initial cost of the stove. As the global benefit is much greater than the cost, which is borne entirely by Ethiopia, international transfers would be warranted to support expansion of Mirt adoption.

The potential of biogas technology in fuelwood saving and carbon emission reduction in Central Rift Valley, Ethiopia

The rapid rate of deforestation, combined with Ethiopia's rapid population growth, has resulted in increased energy scarcity, high greenhouse gas (GHG) emissions, and climate change. Biogas technology has recently been described as one of the most promising solutions to the problems of deforestation, energy supply, and climate change. Therefore, this study was aimed to investigate the potential of biogas technology in fuelwood saving and carbon emission reduction in the Central Rift Valley of Ethiopia. A multi-stage sampling procedure was employed to select a sample of 192 households (HH) (68 biogas adopters and 124 non-adopters). To conduct the Kitchen efficiency test, 25 test subjects were chosen at random from each category. The data were analyzed using descriptive statistics and an independent-sample t-test. The energy source for cooking and heating were fuelwood, biogas, animal dung, agricultural residue, and charcoal were the most common energy source for domestic use, accounting for 46.9%, 35.4%, 9.4 %, 5.2 %, and 3.1%, respectively. Kerosene lamps, battery cells, and tiny solar panels were utilized by 35 %, 32.4 %, and 18 % of respondents, respectively, for lighting. The most widely used woody plants for domestic energy usage were Eucalyptus camaldulensis and Eucalyptus saligna, according to the findings. The digester size of 6m3 was used in 93 (56.5%) of the 165 biogas plants, while 8m3 and 10m3 digesters were used in 69 (43.5%) and 3 (1.8%) of the plants, respectively. Hence, the annual fuelwood savings from using biogas technology per household was calculated to be 1856.78 kg per year, with an annual Carbon dioxide (CO2) emission reduction capacity of 2.75 tons per biogas plant. Consequently, it was projected that all functional biogas plants (111) would save around 305.25 tons of CO2e per year. Generally, Biogas has been proven to be a viable technique for reducing reliance on forest resources and mitigating climate change in general. As a result, the country's energy sector should encourage families to embrace biogas technology to enhance fuelwood availability and reduce carbon emissions.

Low-cost interventions to reduce emissions and fuel consumption in open wood fires in rural communities: Evidence from field surveys

We evaluate the impact of a grass-roots campaign promoting adoption of simple modifications to cooking fires in rural communities in Western Kenya. The modifications consist of adding rock-beds to open fires or simple woodstoves, increasing airflow, improving combustion efficiency, and decreasing the distance between the fire and cooking pot, which improves heat transfer. The campaign was sponsored by Sun24, a US-based non-profit organization. They trained women leaders active in a local Anglican diocese consisting of 9200 families. The women returned to their communities and held their own trainings at local parishes. We randomly sampled 1362 households from those communities to understand the impact of the campaign. 67% of surveyed families were aware of rockbeds: 51% had attended trainings themselves and 16% heard about rockbeds from relatives or neighbors. 85% of the families that had heard about rockbeds installed them at home and continued to use them for many months after first hearing about them. Nearly all users express a high degree of satisfaction with rockbeds and 67% of trained respondents report cooking two or more meals daily on with rockbeds. We examined variation in weekly and daily frequency of use and find larger households are twice as likely to use rockbeds daily and to cook all their meals with rockbeds than smaller households (p < 0.01). Respondents that were trained by Sun24 or women leaders were nearly three times as likely to use rockbeds daily than respondents who heard about rockbeds by word-of-mouth (p < 0.01). Among households reporting daily use, better educated respondents were nearly twice as likely to use rockbeds for all meals. However, respondents who owned charcoal or LPG stoves were 30% and 60% less likely to use rockbeds for all their meals than other respondents (p < 0.05, p < 0.01). Using a regional estimate of “non-renewable biomass” of 36%, we estimate annual emission reductions of roughly 480 kg of CO2-equivalent for each adopter. Sun24 invested roughly USD 700 in training women leaders and facilitating rockbed adoption in thousands of rural households. Previous research found that median fuelwood savings of nearly 30% when families modified open fire stoves with rockbeds. Applying this average to all adopting families results in annual wood savings of 390 kg per family or 2900 tons per year across the diocese. Using a regional estimate of “non-renewable biomass” and assuming rockbed use persists for 5 years, total emission reductions would be 11.8 tCO2e at a mitigation cost of just USD 0.06 per ton CO2e making rockbeds a cost-effective mitigation strategy.

Does Providing Improved Biomass Cooking Stoves Free-of-Charge Reduce Regular Usage? Do Use Incentives Promote Habits?

This article uses a field experiment to evaluate effects of monetary treatments on usage intensity of an important improved biomass-burning cookstove promoted in Ethiopia. Understanding whether, how much and why improved stoves are used are important, because use frequency critically determines fuelwood savings and related benefits. We find that distributing stoves free-ofcharge is at least as effective for promoting short-run adoption as requiring payments or offering usage incentives. Free distribution is most effective at promoting both high and increasing levels of longer-run regular use. First period incentives do not better promote usage habits compared with the other two treatments.

Biochar from cookstoves reduces greenhouse gas emissions from smallholder farms in Africa

Biochar produced in cookstoves has the potential to contribute to negative carbon emissions through sequestration of biomass carbon while also providing other benefits for sustainable development, including provision of clean renewable energy and increased yields in tropical agriculture. The aim of the reported research was to estimate effects on food production, household energy access and life cycle climate impact from introduction of biochar-producing cookstoves on smallholder farms in Kenya. Participatory research on biochar production and use was undertaken with 150 Kenyan smallholder farming households. Gasifier cookstove functionality, fuel efficiency and emissions were measured, as well as biochar effects on agricultural yields after application to soil. Cookstoves provided benefits through reduced smoke, fuel wood savings and char production, but challenges were found related to labour for fuel preparation, lighting and refilling. On-farm trials with varying rates of biochar inputs, in combination with and without mineral fertilizers, have led to a sustained increase of maize yields following one-time application. The climate impact in a life cycle perspective was considerably lower for the system with cookstove production of biochar and use of biochar in agriculture than for current cooking practices. Climate benefits from biochar production and use are thus possible on smallholder farms in sub-Saharan Africa, through reduced use of biomass in cooking, reduced emissions of products of incomplete combustion and sequestration of stable biochar carbon in soils. Biochar-producing cookstoves can be implemented as a climate change mitigation method in rural sub-Saharan Africa. Successful implementation will require changes in cooking systems including fuel supply, as well as farming systems, which, in turn, requires an understanding of local socio-cultural conditions, including power relations and gender aspects.

A cost-benefit analysis of livelihood, environmental and health benefits of a large scale water filter and cookstove distribution in Rwanda

Public health interventions targeting contaminated drinking water and indoor air pollution may help to reduce two of the leading causes of death among children under 5 in Rwanda - diarrhea and pneumonia. These interventions also have the potential to provide economic benefits, including reduction in expenditures on fuelwood and time spent on fuelwood collection, environmental benefits through reductions in deforestation and greenhouse gas emissions, and additional economic benefits attributable to health impacts. We evaluate one such large scale intervention, the Tubeho Neza program in Western Rwanda using a cost-benefit analysis. This paper estimates monetized program benefits related to fuelwood savings, time savings, environmental and health benefits, which are then compared to the overall program cost, over a 5 year project year period. The total program cost is estimated at over $11.91 million, and total benefits at the means valued at over $66.67 million, for an estimated mean cost-benefit ratio of over 5.6. A sensitivity analysis of the major factors indicated a cost-benefit ratio range of approximately 1–16. The primary benefit identified is the environmental impact of woodfuel savings attributable to the improved cookstoves. This study estimates 118,000 tonnes of annual woodfuel savings in the Western Province may be attributable to the program in year 1, decreasing to 65,000 tonnes in year 5. These estimates suggest that this program may help to compensate for the government of Rwanda's projected regional woodfuel deficit of 106,000 tonnes per year by 2020. Overall, this study suggests that the Tubeho Neza program provides benefits in excess of the program costs.

Fuel savings, cooking time and user satisfaction with improved biomass cookstoves: Evidence from controlled cooking tests in Ethiopia

Continued high reliance on traditional biomass fuels and stoves in developing countries gives rise to several human health, environmental, and livelihood issues. However solid data on the performance of improved biomass cooking stoves remains scarce. This paper provides controlled cooking test (CCT) evidence on fuel savings from a promising improved biomass cooking stove in Ethiopia. The stove is called Mirt (meaning “best” in Amharic), and is used to bake injera, the staple food in much of Ethiopia. Injera preparation accounts for about half the primary energy consumed in the country. We find that the Mirt stove offers fuel savings of 22% to 31% compared with a traditional three-stone tripod, with little or no increase in cooking time. Fuel savings in the CCTs are significant, but are substantially smaller than in laboratory testing. Users also generally report high levels of satisfaction with the stove, which is crucial for successful large-scale adoption. The fuelwood savings increase and cooking times decline over time, suggesting the importance of user experience and learning. Though our results are robust to different ways that the stoves were rolled out, conclusions regarding acceptability of the stove are still indicative, because of the CCT methodology we employ. Despite the limitations of our study, the findings suggest that the Mirt stove could have positive welfare effects for households who adopt it.

Closing the gap between lab and field cookstove tests: Benefits of multi-pot and sequencing cooking tasks through controlled burning cycles

There is a critical need for developing wood-burning cookstoves lab tests that better reflect their field performance, and that can be used to complement existing standard tests. This is particularly true for Plancha-type cookstove stoves, widely disseminated in Latin America, where existing tests, like Water Boiling Test (WBT) and Controlled Cooking Test (CCT), are either not well suited to these stoves or do not capture the simultaneous and sequential arrangement of local cooking practices –i.e., multi-pot cooking, pre-heating of meals, and use of residual heat. In this paper, we developed a “controlled cooking cycle” or “controlled burning cycle” (CBC) test to study the benefits, in terms of fuelwood and pollutants emissions savings, of multi-pot cooking arising from the integration of cooking tasks. Tests were conducted on the Patsari stove, a plancha-type stove that has been widely disseminated in Mexico and in other regions of Central America. We first used CCTs to evaluate the comparative energy and emissions performance of the Patsari stove relative to a traditional U-shaped open fire (U-type) for the most common cooking practices carried out in the Purepecha Region of Michoacan. We also compared results from the CBC multi-pot cooking with results from simply conducting the cooking tasks in series. All the CCTs and CBCs were carried out in a simulated kitchen at GIRA facilities in Patzcuaro, Michoacan, Mexico with two local cooks who performed all the cooking tasks in the traditional/typical manner of the region. Results from CCTs showed Patsari benefits relative to the open fires, in terms of fuelwood consumption and CO and PM2.5 emissions savings, vary among cooking tasks and range from negligible to 63% depending on the parameter and the task. The sequential cooking and integration of these tasks in a CBC result in average savings of 65% for CO, 65% for PM2.5 and 35% for fuelwood relative to the U-type, and of between 30% and 44% savings with respect to simply conducting the cooking tasks in series in the same stove. The CBC fuelwood savings obtained here are comparable with field results from Kitchen Performance Tests (KPT) conducted regionally by other authors. The results confirm that multi-pot cooking and a smart sequential integration of tasks developed by local users are key to achieve the maximum benefits from plancha-type stoves, and need to be much better reflected in standard lab tests.

Spatiotemporal modeling of fuelwood environmental impacts: Towards improved accounting for non-renewable biomass

The extraction and burning of woody biomass at rates exceeding re-growth (i.e. non-renewable extraction) results in net emissions of CO2. Quantification of the amount of non-renewable woody biomass through a robust and widely applicable method is urgently needed for a wide variety of applications including cookstove carbon-offset projects, national GHG inventories, and sustainable forest management strategies under REDD+. Within this context, we developed “Mofuss” (Modeling fuelwood savings scenarios), a dynamic model that simulates the spatiotemporal effect of fuelwood harvesting on the landscape vegetation and that accounts for savings in non-renewable woody biomass from reduced consumption. The model was tested in western Honduras where collected and marketed fuelwood is used by the residential sector in both urban and rural settlements. We argue that geospatial modeling, aimed at representing real situations more closely while integrating uncertainty, should be used in calculations of carbon savings from cookstove projects or fuel switching interventions.

Fuelwood Savings and Carbon Emission Reductions by the Use of Improved Cooking Stoves in an Afromontane Forest, Ethiopia

In many Sub-Saharan African countries, fuelwood collection is among the most important drivers of deforestation and particularly forest degradation. In a detailed field study in the Kafa region of southern Ethiopia, we assessed the potential of efficient cooking stoves to mitigate the negative impacts of fuelwood harvesting on forests. Eleven thousand improved cooking stoves (ICS), specifically designed for baking Ethiopia’s staple food injera, referred to locally as “Mirt” stoves, have been distributed here. We found a high acceptance rate of the stove. One hundred forty interviews, including users and non-users of the ICS, revealed fuelwood savings of nearly 40% in injera preparation compared to the traditional three-stone fire, leading to a total annual savings of 1.28 tons of fuelwood per household. Considering the approximated share of fuelwood from unsustainable sources, these savings translate to 11,800 tons of CO2 saved for 11,156 disseminated ICS, corresponding to the amount of carbon stored in over 30 ha of local forest. We further found that stove efficiency increased with longer injera baking sessions, which shows a way of optimizing fuelwood savings by adapted usage of ICS. Our study confirms that efficient cooking stoves, if well adapted to the local cooking habits, can make a significant contribution to the conservation of forests and the avoidance of carbon emission from forest clearing and degradation.

Validación y evaluación comparativa de la eficiencia de una estufa de leña mejorada bajo condiciones controladas y prueba de campo

Para determinar la eficiencia y el ahorro potencial de leña de un nuevo prototipo de estufa de leña, se ejecutaron tres protocolos utilizados internacionalmente para este propósito: (1) la prueba de ebullición de agua (WBT sus siglas en inglés), que evalúa la eficiencia térmica, el tiempo de ebullición, la tasa de incineración y el consumo específico de combustible (CEC) de la estufa; (2) la prueba de cocción controlada (CCT, sus siglas en inglés), que se aplicó en 30 hogares para determinar la eficiencia de la estufa en función del CEC; (3) la prueba de funcionamiento en cocina (KPT, sus siglas en inglés), que se aplicó en 30 hogares para medir el impacto real de la estufa mejorada en condiciones de campo. Se pudo establecer que la eficiencia térmica de la estufa es del 15%, lo que supone un ahorro en el consumo de leña del 33%. Los resultados de la prueba CCT indicaron disminución de 13,4% en el CEC, mientras que la prueba KPT reveló disminución de 11,6%. Los resultados de la investigación ratifican lo encontrado por otras investigaciones sobre el tema: la eficiencia de una estufa lograda bajo condiciones controladas no parece guardar relación con los ahorros de leña que se obtienen cuando una estufa es introducida en ambiente real de cocción.

Beyond fuelwood savings: Valuing the economic benefits of introducing improved biomass cookstoves in the Purépecha region of Mexico

Half of the world population relies on biomass for cooking, with very significant health as well as climate change impacts. Improved cookstoves have been disseminated as an alternative to reduce these impacts. However, few detailed studies about the economic benefits of improved cookstoves (ICS) interventions, including environmental and health co-benefits, exist to date. In this paper we perform a comprehensive economic evaluation of a dissemination program of ICS in rural Mexico. The resulting cost–benefit analysis (CBA) of the Patsari improved cookstove is presented, utilizing estimation of direct costs and benefits, including fuelwood savings, income generation, health impacts, environmental conservation, and reduction in greenhouse gas emissions. The analysis is based on comprehensive data obtained through monitoring studies carried out in the Study Area from 2003 to the present. Results show that Patsari cookstoves represent a viable economic option for improving living conditions of the poorest inhabitants of rural Mexico, with benefit/cost ratios estimated between 11.4:1 and 9:1. The largest contributors to economic benefits stemmed from fuelwood savings and reductions in health impacts, which constituted 53% and 28% of the overall benefit, respectively.

Energy performance of wood-burning cookstoves in Michoacan, Mexico

There have been few detailed assessments of the actual impacts of improved stove interventions in rural communities, although many improved stove projects have reported overall efficiencies from tests in simulated kitchens using water-boiling tests (WBTs). This paper presents an integrated energy evaluation of the Patsari cookstove, an efficient wood-burning cookstove developed in Mexico that has recently obtained international recognition, in comparison to traditional cookstoves in rural communities of Michoacan, Mexico. The evaluation uses three standard protocols: the WBT, which quantifies thermal efficiency and firepower; the controlled cooking test (CCT), which measures specific energy consumption associated with local cooking tasks, and the kitchen performance test (KPT), which evaluates the behavior of the stoves in-field conditions and estimates fuel savings. The results showed that the WBT gave little indication of the overall performance of the stove in rural communities. Field testing in rural communities is of critical importance, therefore, in estimating the benefits of improved stoves. In the CCT for tortilla making, the main cooking task in Mexican rural households, Patsari stoves showed fuelwood savings ranging from 44% to 65% in relation to traditional open fires ( n=6; P<0.05). These savings were similar in magnitude to the average energy savings from KPT before and after Patsari adoption of 67% ( n=23; P<0.05) in rural households exclusively using fuelwood. Similar energy savings of 66% for fuelwood and 64% for LPG, respectively, were also observed in households using mixed fuels. With sound technical design, critical input from local users and proper dissemination strategies, therefore, improved stoves can significantly contribute to improvements in the quality of life of rural people with potential benefits to the surrounding environment.

Assessment of sustainable energy potential of non-plantation biomass resources in Thailand

Abstract This paper discusses the importance of biomass as a source of energy in Sri Lanka and assesses the sustainable national non-plantation biomass resource potential. Different biomass sources, both direct and indirect, are considered in the analysis. The direct sources include agricultural and wood residues, animal manure, municipal solid waste and wastewater. The indirect sources include fuelwood conservation through efficiency improvements and fuelwood savings through fuel switching. The potential of each source is estimated for the base year 1997 as well as for the years 2005 and 2010. The total energy potential of these sources in 1997, 2005 and 2010 is 120 PJ, 133 PJ and 142 PJ, respectively. The corresponding electricity generation potentials are 8.34, 9.24 and 9.85 TWh, respectively for a conversion efficiency of 25%. The annual electricity demand in Sri Lanka 1997 was 4.20 TWh and the forecast values for the years 2005 and 2010 are 10.50 and 15.60 TWh respectively; this implies that the biomass sources could contribute significantly towards meeting the future electricity requirement.

Fuelwood-fired cookstoves in Sri Lanka and related issues

The historical development of cookstoves and improved cookstove (ICS) development and dissemination programmes conducted in Sri Lanka are reviewed and the current utilization patterns of different cookstoves are estimated. Performance characteristics and emission factors of most commonly used stove categories are presented. Environmental and health implications of domestic cooking are discussed. Impacts of dissemination of ICSs, in terms of fuelwood savings and emission reductions, are also estimated. The results indicate that only 12% of the fuelwood used for cooking in the domestic sector is consumed in ICSs and around 41% of fuelwood could be saved by dissemination of ICSs. This would lead to a considerable reduction in the emissions generated from fuelwood use in domestic cooking.

Improved cookstoves in rural India: how improved are they?: A critique of the perceived benefits from the National Programme on Improved Chulhas (NPIC)

The National Programme on Improved Cookstoves (NPIC) was started by the Ministry of Non-conventional Energy Sources (MNES), Government of India, in 1985 to achieve the twin objectives of fuelwood conservation and smoke reduction in kitchens. NPIC has overseen the installation of 28 million improved cookstoves, saving nearly 20 million tons of firewood per year. These achievements, though seemingly impressive, are not realistic as they are based on certain assumptions, particularly regarding the life expectancy of stoves. This paper examines the various assumptions made in such calculations and tries to arrive at some realistic numbers regarding fuelwood savings, which can be used to evolve a policy for refining the NPIC further.

A social and environmental evaluation of fuel-efficient cook-stoves and conservation in Uganda

A significant factor contributing to deforestation is the expanding human populations' increasing demands on forests and forest products. In many areas, rural households rely solely on fuelwood collected from the forest for their domestic energy supply. Fuel-saving stoves, or improved cook-stoves, have been introduced to reduce fuelwood consumption and thus alleviate deforestation, but there is frequently little or no formal monitoring and evaluation of programmes; their success as both a development and a resource-conservation tool is therefore undetermined. A programme was implemented in communities surrounding two national parks in western Uganda to compare domestic fuelwood consumption of an improved cook-stove and the traditional cooking fire, and assess the attitudes of stove users and non-users towards the improved stove and resource conservation. A kitchen performance test conducted in 100 households in Kiziba, Kahangi and Matayisa/Bundinyama parishes showed that fuelwood consumption did not differ significantly between improved and traditional stoves under actual field conditions. Household surveys showed that respondents in all three parishes had positive perceptions of the improved cook-stove. Perceived advantages of the improved stove included the ability to cook more than one item at once, fuelwood savings, quick cooking, and smoke/accident reduction. Many problems cited with the stove were technical, such as chimney malfunctions and pot-holes being too large or small to accommodate cooking pots. Cost of the stove was the primary reason for non-adoption. Improved-stove users were more concerned with forest conservation than were non-users. The need for monitoring and evaluation of improved-stove programmes is strongly indicated if they are to continue to be implemented as tools for resource conservation.

Fuel switching or multiple cooking fuels? Understanding inter-fuel substitution patterns in rural Mexican households

Ninety-one per cent of Mexican rural households and 11% of urban households cook with fuel wood. Fuel wood represents 50% of total residential energy use in the country. This paper presents the results of a detailed study of the patterns of household fuel wood use and inter-fuel substitution in three villages of rural Mexico. All residents in the three villages cook with fuel wood, and between 20 and 43% of them also use LPG (liquefied petroleum gas) for this task, depending on the village. Average household fuel wood demand ranges between 53 and 60 GJ/yr for fuel wood only users and from 40 to 57 GJ/yr for mixed fuel wood-LPG users, depending on the village. Cooking practices are described together with their energy use. Kitchen performance tests and controlled cooking tests (CCT) were applied in two villages to measure savings in household fuel wood use from partially switching to LPG. The analysis shows that energy and fuel wood savings are much lower than those that may be expected on a purely technical basis. In fact, fuel wood is very seldom replaced entirely, even in households that have been using LPG for many years. Rather than switching, households follow a multiple fuel strategy which gives them the advantages of both fuels. There is a strong pattern of fuel preferences by type of dish and cooking task. Fuel wood is seen as a fuel with advantages that go beyond price and include cultural considerations. Lorena-type improved woodburning cookstoves might prove particularly useful for multiple fuel users as they show savings of up to 50% for tortilla-making compared with the traditional stoves in CCT.